Water-based drilling fluid additive containing talc and cellulose

ABSTRACT

A drilling fluid additive is provided wherein the additive is manufactured by a method comprised of admixing colloidal solids such as talc with a combination of oil and glycol or cellulose to create a suspended mixture to thereby allow the colloidal solids to be pre-wet, treated or coated with the oil/glycol combination or the cellulose; and then admixing copolymer beads to the suspended mixture.

RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.10/090,201 pending, entitled Water-Based Drilling Fluid AdditiveContaining Talc & Carrier which was filed on Mar. 5, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a drilling fluid additive comprising talc andcellulose or talc, an oil and a glycol. More specifically, the presentinvention relates to a method of manufacturing a drilling fluid additiveby admixing talc with cellulose or with oil/glycol combination tothereby allow the surface of the talc to be pre-wet or coated with thecellulose or the oil/glycol combination prior to adding the additive toa drilling fluid.

2. Description of the Related Art

New technology in drilling for oil and gas now includes horizontaldrilling. The horizontal drilling concept exposes more surface area ofthe producing zone than the conventional vertical drilling operations.For example, if a producing zone is fifty feet in thickness and avertical well is drilled through such a zone, then only fifty feet ofthe producing zone will be exposed for production. In contrast, ahorizontally drilled well may penetrate the producing sand or zone byone thousand feet or more. The amount or volume of oil or gas productionis directly proportional to the horizontal penetration in feet into theproducing sand or zone. In horizontal or directional drilling where thedrill pipe must bend in order to achieve the desired penetration intothe producing zone, friction becomes a major problem. The primary sourceof friction is directly related to the adhesion of the drilling assemblyto the wall cake which lines the drilled well bore. The capillaryattractive forces generated by the adhesion of the drilling assembly tothe wall cake are directly proportional to the amount or footage of thedrilling assembly exposed to the surface of the wall cake.

In horizontal or directional wells, many methods have been used in orderto reduce friction between the drilling assembly and the wall cake. Onesuch method would be to add a liquid lubricant to the drilling fluid inorder to reduce the coefficient of friction of the drilling fluid. Theseliquid lubricants include oils, such as hydrocarbon based oils,vegetable oils, glycols, etc. These liquid lubricants will usuallyreduce the coefficient of friction of the drilling fluid resulting in areduction of friction between the drilling assembly and the wall cake ofthe well bore.

When the liquid lubricant is added to the drilling fluid, it has severaloptions as to how it will react. One option is that the lubricantremains isolated and does not mix well with the drilling fluid. A secondoption is that the lubricant emulsifies with the water in the drillingfluid to form an oil-in-water emulsion. Still another option is the oilattaching itself to the commercial solids in the drilling fluid or tothe drilled cuttings or drilled solids. In certain circumstances, someof the liquid lubricant might be deposited or smeared onto the wall cakeof the well bore. The ideal scenario would be to have all of the liquidlubricant deposited on the wall cake.

Those experienced in drilling fluid engineering know that a thin, tough,pliable, and lubricious wall cake is most desirable. The integrity of awall cake is determined by several factors. The thickness of a wall cakeis directly proportional to the amount of liquid leaving the drillingfluid, and being forced into the wall of the well bore by hydrostaticpressure. The thickness of the wall cake is also determined by the typeand particle size of the solids in the drilling fluid. Particle SizeDistribution, or PSD is important to the wall cake integrity. Experts indrilling fluids also know that materials such as bentonite clay,starches, lignites and polymers are all used to build acceptable wallcakes. It is known in the prior art that various food grade vegetableoils are acceptable lubricants when used alone in water-based drillingfluids. It is also known in the prior art that round co-polymer beadswhen used alone in water-based drilling fluids function as a goodfriction reducer. However, much more is required to improve the wallcake integrity and lubricity of most well bores. In addition, there isno technology or process in the prior art that improves the lubricationor friction reducing capacity of the copolymer beads.

Furthermore, the solids control equipment used on the drilling rigstoday is far superior as to what was used 15 to 20 years ago. In thepast, drilling rig shale shakers would probably be limited to screensizes of about 20-40 mesh on the shakers. These coarser mesh screenswould allow pieces of shale and the drilled formation to pass throughthe shaker screens back into the drilling fluid and then recirculatedback down the well bore. As these larger than colloidal size particlesmake their way back up the well bore to the surface, the action of thedrilling assembly rotating within the well bore forces these largerparticles into the surface of the well bore. For example: a 20×20 meshshaker screen would allow a drilled cutting sized at 863 microns or0.0340 inches to pass through it and then the cutting would be returnedto the well bore and some of these 863 micron cuttings would eventuallybe embedded into the wall cake. This would give the wall cake surface atexture resembling that of coarse sandpaper. These larger particleswould allow the drilling fluid to channel and pass between the drillingassembly and the wall cake thereby reducing the negative effect of thecapillary attractive forces generated by the close contact of thedrilling assembly with the wall cake. The instances of the drillingassembly becoming stuck to the wall cake when less efficient solidscontrol equipment, such as shale shakers, was used much less than it istoday. The more efficient shale shakers today are a great improvementfor the drilling fluids but the instances of sticking the drillingassembly are higher. The reason for a higher rate of stuck drillingassemblies today could be blamed on cleaning the drilling fluid toefficiently. Today many drilling rigs utilize cascading shale shakers,which eventually pass the drilling fluid through 200 mesh or 74 micronscreens. This is very positive for controlling the percentage of drilledsolids in the drilling fluid but it also affects the texture or surfaceof the wall cake. The finer the solids on the surface of the wall cakeare, the greater the capillary attractive forces will be between thedrilling assembly and the wall cake.

The present invention provides a method of enhancing the surface of thewall cake. In order to accomplish this, the invention provides a method,which adds something to improve the texture of the surface of the wallcake, and then adds something to prevent large amounts of water fromleaving the drilling fluid then passing through the wall cake into theformation. The present invention also provides a carrier for thecolloidal solids and beads, which also acts as a lubricant for thedrilling fluid. The present invention further provides a process thatreduces the effect of capillary attractive forces between the drillingassembly and the wall cake, thereby reducing the tendency of thedrilling assembly to become stuck. In high angle directional wells wheredown hole motors are used to rotate the drill bit and the drill piperemains stationary, it is important that the drilling assembly can slideas the drilling bit cuts more holes. The present invention improves theability to slide while drilling as stated above.

SUMMARY OF THE INVENTION

In one embodiment, the present invention relates to a drilling fluidadditive manufactured by a method comprising of: admixing talc with oiland glycol to create a suspended mixture, the suspended mixture allowingthe surface of the talc to be pre-wet with the oil and the glycol priorto adding the mixture to a drilling fluid. In another embodiment, thedrilling fluid additive further comprises admixing copolymer beads tothe suspended mixture. In still another embodiment, the talc has anaffinity for oils, esters, glycols, cellulose and olefins. The carrierof the present invention also functions as a lubricant.

In yet another embodiment, the beads have a specific gravity at fromabout 1.0 to about 1.5 and a size from about 40 microns to about 1500microns. In still yet another embodiment, the beads are comprised ofstyrene and divinylbenzene. In a further embodiment, the solids have asize range from about 2 microns to about 40 microns. In still a furtherembodiment, the solids are comprised of talc. For purposes of thisinvention, talc is a mineral, which is magnesium silicate. Talc isextremely hydrophobic and thus, repels water. Since talc has excellentwater repellant properties, it would be advantageous to have the surfaceof the walls of the base mud wall cake to be completely covered orcoated with talc.

In yet a further embodiment, the oil of the present invention consistessentially of oils, hydrocarbon oils, vegetable oils, mineral oils,paraffin oils, synthetic oils, diesel oils, animal oils and soybean oiland mixtures thereof. In still yet a further embodiment, the glycol ofthe present invention consist essentially of polypropylene glycol,polyethoxylated glycol, polybutylene glycol, polyethylene glycol,propylene glycol, polyester polyol-poly(oxyethylene-oxy) propyleneglycol, polyoxyalkylene glycol ethers and mixtures thereof.

In still another further embodiment, the talc comprises from about 2% toabout 50% of the additive of the present invention. In yet anotherfurther embodiment, the oil comprises from about 50% to about 98% of theadditive. In another embodiment, the glycol comprises from about 10% toabout 98% of the additive. In still yet another embodiment, the beadscomprises from about 2% to about 50% of the additive.

In a further embodiment, the present invention relates to a drillingfluid additive manufactured by a method comprising of: admixing talcwith cellulose to create a suspended mixture, the suspended mixtureallowing the surface of the talc to be coated with the cellulose priorto adding the mixture to a drilling fluid. In still a furtherembodiment, the drilling fluid additive further comprises admixingcopolymer beads to the suspended mixture. In yet another embodiment, thesuspended mixture is admixed with oil coated polymer or copolymer beads.For purposes of this invention, cellulose applies to both the liquid andsolid (powder) forms of cellulose and the term coated shall apply to dryand wet coatings and/or treatments of cellulose. In one embodiment, thetalc is pre-wet with the liquid cellulose. In another embodiment, thetalc is coated with solid (powder) cellulose.

In yet another embodiment, the beads have a specific gravity at fromabout 1.0 to about 1.5 and a size from about 40 microns to about 1500microns. In still yet another embodiment, the beads are comprised ofstyrene and divinylbenzene. In a further embodiment, the talc has a sizerange from about 2 microns to about 40 microns. In another furtherembodiment, the cellulose consists essentially of polyanionic cellulose,polyanionic cellulose polymer, and carboxymethylcellulose.

In still another further embodiment, the talc comprises from about 2% toabout 50% of the additive of the present invention. In yet anotherfurther embodiment, the cellulose comprises from about 5% to about 98%of the additive. In still yet another embodiment, the beads comprisesfrom about 2% to about 50% of the additive.

In another embodiment, the present invention relates to a method ofmanufacturing a drilling fluid additive mixture, the method comprises:shearing talc with oil and glycol to create a suspended mixture tothereby allow the surface of the solids to be pre-wet with the oil andglycol; and admixing copolymer beads to the suspended mixture. In yetanother embodiment, the solids and the beads having an affinity foroils, esters, glycols, cellulose and olefins. In another embodiment, thebeads are sheared with the suspended mixture until a homogeneous mixtureis formed. The order of mixing the oil and the glycol can be alternated.

In still yet another embodiment, the beads have a specific gravity atfrom about 1.0 to about 1.5 and a size from about 40 microns to about1500 microns. In a further embodiment, the beads are comprised ofstyrene and divinylbenzene. In yet a further embodiment, the talc has asize range from about 2 microns to about 40 microns. In another furtherembodiment, the carrier-consists essentially of oils, vegetable oils,mineral oils, paraffin oils, esters, glycols, cellulose and olefins. Inyet another further embodiment, the carrier comprises polypropyleneglycol. The combination of hydrophobic talc and polypropylene glycol asan additive, functions as an excellent plugging agent. For purposes ofthis invention, the term plugging agent is defined as a solid having aparticular size and shape so as to plug or seal off the surfacemicro-fractures of a porous sand, shale, or formation being drilled.

In still another further embodiment, the talc comprises from about 2% toabout 50% of the additive of the present invention. In yet anotherfurther embodiment, the oil comprises from about 50% to about 98% of theadditive. In another embodiment, the glycol comprises from about 10% toabout 98% of the additive. In still yet another embodiment, the beadscomprises from about 2% to about 50% of the additive.

In another embodiment, the present invention provides a method ofmanufacturing a water-based drilling fluid, the method comprising:shearing talc with at oil and a glycol to create a suspended mixture tothereby allow the solids to be pre-wet with the oil and the glycol;admixing copolymer beads to the suspended mixture thereby allowing saidbeads to be pre-wet with the oil and the glycol; adding the suspendedmixture to a water-based drilling fluid; and adding the fluid with theadditive to a well bore.

In yet another embodiment, the solids and the beads have an affinity foroils, esters, glycols, cellulose and olefins. In still anotherembodiment, the beads have a specific gravity at from about 1.0 to about1.5 and a size from about 40 microns to about 1500 microns, and thebeads are comprised of styrene and divinylbenzene. In yet anotherembodiment, the talc has a size range from about 2 microns to about 40microns. In a further embodiment, the oil consists essentially ofsoybean oil, hydrocarbon oils, vegetable oils, mineral oils, paraffinoils, animal oils and mixtures thereof. In still another furtherembodiment, the glycol consists essentially of polypropylene glycol,polyethoxylated glycol, polybutylene glycol, polyethylene glycol,propylene glycol, polyester polyol-poly(oxyethylene-oxy) propyleneglycol, polyoxyalkylene glycol ethers and mixtures thereof. In a furtherembodiment, the talc of the present invention functions as a suspensionagent and by making the talc oil wet, it becomes more hydrophobic andthus, more effective. In another further embodiment, the combination oftalc and oil functions as an excellent plugging agent.

In still another further embodiment, the talc comprises from about 2% toabout 50% of the additive of the present invention. In yet anotherfurther embodiment, the oil comprises from about 50% to about 98% of theadditive. In another embodiment, the glycol comprises from about 10% toabout 98% of the additive. In still yet another embodiment, the beadscomprises from about 2% to about 50% of the additive.

In another embodiment, the present invention relates to a water-baseddrilling fluid additive comprising talc and at least one carrier whereinthe carrier may be oils, esters, glycols, cellulose and olefins orcombinations thereof. In still another embodiment, the talc is coated ortreated with the carrier converting the surface of the talc to a carriertreated or coated surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the present invention. These drawings are incorporatedin and constitute a part of this specification, illustrate one or moreembodiments of the present invention, and together with the description,serve to explain the principles of the present invention.

FIG. 1 is a graph representing talc particle size versus volume inpercent; and

FIG. 2 is a graph representing the percent of beads suspended in oilversus the talc concentration as percent by weight of oil.

Among those benefits and improvements that have been disclosed, otherobjects and advantages of this invention will become apparent from thefollowing description taken in conjunction with the accompanyingdrawings. The drawings constitute a part of this specification andinclude exemplary embodiments of the present invention and illustratevarious objects and features thereof.

DETAILED DESCRIPTION OF THE INVENTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousforms. The figures are not necessary to scale, some features may beexaggerated to show details of particular components. Therefore,specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a basis for the claims and asa representative basis for teaching one skilled in the art to variouslyemploy the present invention.

The present invention provides a process that includes selectingspecific materials having different particle sizes and then pre-wettingeach particle with an environmentally acceptable lubricant prior toadding these particles to the water-based drilling fluid. This processproduces much improved wall cake integrity and lubricity. The presentinvention also teaches that food grade vegetable oils are excellentcarriers for various solid friction reducers and wall cake enhancers.The present invention has also discovered that pre-wetting the roundcopolymer beads with a food grade vegetable oil prior to adding thecopolymer beads to the drilling fluid improves the lubrication orfriction reducing capacity of the copolymer beads. The other criterionis that the products and its components have to be environmentallyfriendly.

In accordance with the manufacturing process of the present invention,talc powder is sheared with an environmentally friendly oil or liquidlubricant, which repels water. The shearing should continue until eachor most of the organophilic or hydrophobic talc particles are coatedwith the oil or liquid lubricant. In one embodiment, the talc powdermost preferred would be one with a particle size from about 1 micron toabout 20 microns and one which would produce a bell shaped curve havingthe majority of the particles in the 2 micron to 8 micron size, as shownin FIG. 1.

The polymeric beads of the present invention should be a solid particle,preferably round and have a specific gravity close to 1.0 and have asize from about 100 microns to about 900 microns. The beads must alsohave an affinity for oils, esters, olefins and glycols, etc. It wasdetermined that a copolymer bead manufactured by Dow Chemical comprisedof styrene and divinylbenzene would be acceptable.

The colloidal solids of the present invention should have a size rangeof 2-10 microns since tests have proven that this particle size willbridge sandstone having a permeability of 200 md. The solids must alsohave an affinity for oils, esters, olefins and glycols, etc. In oneembodiment, the solids are talc. The talc of the present invention alsofunctions as an excellent suspending agent in both oils and glycols.FIG. 1 depicts a graphical representation of the particle size of talcand Table 1, as set forth below, represents the result statistics forthe particle size for talc:

TABLE 1 Particle Size Statistics For Talc Dist. Type: Vol Concentration= 0.0136% Vol Density = 2.650 g/cub. cm Spec. SA = 0.5176 sq. m/g MeanDiameters: D (v, 0.1) = 2.40 um D (v, 0.5) = 5.28 um D (v, 0.9) = 11.68um D [4, 3] = 6.30 um D [3, 2] = 4.37 um Span = 1.760E+00 Uniformity =5.495E−01 Size Low (um) In % Size High (um) Under % 0.31 0.00 0.36 0.000.36 0.00 0.42 0.00 0.42 0.00 0.49 0.00 0.49 0.00 0.58 0.00 0.58 0.000.67 0.00 0.67 0.00 0.78 0.00 0.78 0.00 0.91 0.00 0.91 0.02 1.06 0.021.06 0.32 1.24 0.35 1.24 0.94 1.44 1.29 1.44 1.83 1.68 3.12 1.68 2.511.95 5.62 1.95 2.94 2.28 8.57 2.28 5.05 2.65 13.62 2.65 6.89 3.09 20.513.09 7.96 3.60 28.47 3.60 7.81 4.19 36.29 4.19 8.89 4.88 45.18 4.88 9.495.69 54.67 5.69 9.05 6.63 63.72 6.63 8.60 7.72 72.33 7.72 7.61 9.0079.94 9.00 6.35 10.48 86.29 10.48 5.02 12.21 91.31 12.21 3.70 14.2295.01 14.22 2.47 16.57 98.95 16.57 1.46 19.31 99.68 19.31 0.73 22.49100.00 22.49 0.27 26.20 100.00 26.20 0.05 30.53 100.00 30.53 0.00 35.56100.00 35.56 0.00 41.43 100.00 41.43 0.00 48.27 100.00 48.27 0.00 56.23100.00 56.23 0.00 65.51 100.00 65.51 0.00 76.32 100.00 76.32 0.00 88.91100.00 88.91 0.00 103.58 100.00 103.58 0.00 120.67 100.00 120.67 0.00140.58 100.00 140.58 0.00 163.77 100.00 163.77 0.00 190.80 100.00 190.800.00 222.28 100.00 222.28 0.00 258.95 100.00 258.95 0.00 301.68 100.00

The carrier of the present invention may be selected from differentoils, olefins, esters, fatty acids, cellulose and glycols. In anotherembodiment, the carrier may be synthetic oils, diesel oils, rice oils,cottonseed oils, corn oils, safalour oils, linseed oils, coconut oils,vegetable oils, mineral oils, animal oils and paraffin oils. In stillanother embodiment, the carrier is soybean oil. The oil coating on thehydrophobic talc particles enhances the plugging action of the talcacross or into micro fractures in sands, shale and other substances downhole.

In a further embodiment, the present invention relates to a method ofmanufacturing a drilling fluid additive whereby talc and copolymer beadsare added to soybean oil and mixed or sheared until each particle oftalc and each copolymer bead is oil wet. A first sample was produced byaddition of 350 grams of soybean oil with 5 grams of talc and 100 gramsof polymer beads to the oil, and then mixing all the components for 10minutes using a Waring blender. After blending, the mixture was placedin a beaker for observation. The mixture appeared homogeneous andinitially resembled buttermilk. After 5 minutes, the beads began tosettle. After one hour, all the beads settled to the bottom of thebeaker and some of the oil began separating from the mixture and clearoil was present at the upper portion of the beaker. After sittingovernight (10 hours later), the upper portion of the beaker was clearoil and the bottom portion was the talc, beads and oil. Pouring theclear oil off exposed that the beads had settled and packed tightlypreventing the beads from pouring out of the beaker. This sample couldnot be placed in a drum or tank for shipping because the beads wouldsettle and plug the drum or tank.

A second sample was produced by adding talc to the oil and eliminatingthe beads initially. It was discovered that the oil acceptedapproximately 40% by weight of talc. After sitting overnight, there wasno separation between the talc and the oil. At that point, smalladditions of beads were added to the above mixture. The addition of 2%by weight of beads to the talc/oil mixture was encouraging. The beadssettled slightly but did not pack off. As the concentration of the beadswas increased in the mixture, it was discovered that the beads remainedsuspended in the mixture. FIG. 2 depicts graphical representations ofthe talc concentration as percent (%) by weight of oil versus thepercent (%) of beads suspended in oil. FIG. 2 illustrates that as thetalc concentration as a percent (%) by weight of the oil increases, thesuspension qualities of the liquid oil increases. As FIG. 2 illustrates,the talc concentration of 20 percent by weight of the liquid oilsuspends 100 percent of the copolymer beads.

The second sample was then heated to 150 degrees Fahrenheit for 24 hoursand the copolymer beads remained suspended. The mixture was then cooledto 35 degrees Fahrenheit for 24 hours and the copolymer beads remainedsuspended. It was also discovered that the optimum concentration of thebeads was from about 20 percent to about 30 percent by weight of theoil, and the concentration of the talc should be around 20 percent byweight of oil. Although this sample appears to be the best, theconcentration may vary.

The specific examples throughout the specification will enable thepresent invention to be better understood. However, they are merelygiven by way of guidance and do not imply any limitations. Example 1conducted tests on a 9.9 pounds per gallon (ppg) water-based drillingfluid and Example 2 conducted tests on a 16.9 pounds per gallon (ppg)water-based drilling fluid. Example 3 conducted tests on the reductionof capillary forces in both the 9.9 ppg drilling fluid of Example 1 andthe 16.9 ppg drilling fluid of Example 2.

EXAMPLE 1

Test 1: Rheology & HPHT Results

In Example 1, a 9.9 pound per gallon water-based drilling fluid wastested for the (a) the compatibility of the drilling fluid-such asrheology; and the yield point and gels in particular; (b) the highpressure high temp fluid loss-HPHT; (c) the filter cake wt./gram; and(d) the filter cake thickness (in inches). Parameters were first testedon the base mud. By comparison, 2 percent (%) by volume of the oil, talcand the beads mixture was added to the base drilling fluid and mixed for5 minutes on a waring blender. In Test 1 & Table 2, the followingrheology and HPHT results were noted:

TABLE 2 Rheology & HPHT Results BASE & 2% % REDUC- BASE TALC MIXTURETION Density 9.9 PH Meter 10.3 600 rpm 19 22 300 rpm 11 13 200 rpm 8 10100 rpm 5 6 6 rpm 2 1 3 rpm 2 1 PV @ 120 F. 8 9 YP 3 4 Gels 10 sec/10min {fraction (2/13)} {fraction (1/17)} HPHT @ 200 Deg F./ml 12.0 8.033% Cake Wt./g 5.9 5.4  8% Cake Thickness/inch {fraction (3/32)}{fraction (2/32)} 33% MBT/pbb 30 Solid/Oil/Water 10/00/90

The results of Example 1, Test 1 indicate the following: the talc, beadand oil mixture was very compatible with the mud rheology with onlyslight increases in yield point and gels. The HPHT fluid loss wasreduced from 12.0 to 8.0; a 33% reduction, which is excellent. The cakein weight in grams was reduced from 5.9 grams to 5.4 grams, an 8%reduction. The cake thickness in inches was reduced from 3/32 to 2/32, a33% reduction, which is also excellent.

EXAMPLE 1

Test 2: Dynamic Filtration

In Example 1, Test 2, the following dynamic filtration criteria weretested: (a) Fluid loss versus time; (b) Filter cake wt/gram; and (c)Filter cake thickness in inches. The dynamic filtration data of Example1, Test 2 is set forth in Table 3 below:

TABLE 3 DYNAMIC FILTRATION 5 Darcy, 50 Micron Filter Media 200 DegreesF., 600 rpm @ 1000 PSI for 60 Minutes Fluid Loss (ml) BASE & 2% TIME(Minutes) BASE TALC MIXTURE % REDUCTION Initial Spurt 1.5 trace 15 12.65.8 30 17.0 10.0 45 21.2 14.0 60 24.0 16.8 30% Cake Wt/g 10.7 5.8 46%Cake Thickness/Inch {fraction (3/32)} {fraction (2/32)} 33%

The results of Example 1, Test 2 are as follows: after 60 minutes, thedynamic fluid loss was reduced from 24.0 ml to 16.8 ml, a 30% reduction,which is excellent. The cake weight in grams was reduced from 10.7 gramsto 5.8 grams, a 46% reduction, which is also excellent. The cakethickness was reduced from 3/32 to 2/32, a 33% reduction, which isexcellent.

EXAMPLE 1

Test 3: Lubricity Test

Table 4 below shows the test results of the lubricity of the additive astorque is applied.

TABLE 4 LUBRICITY TEST @ 60 rpms Co-efficient of Friction of Water(0.33-0.36) = 0.33; i.e. reading at 150 inch pounds is 33 LubricityReading (electric current required to sustain 60 rpm at applied torque)Applied Torque/Inch BASE & 2% Pounds BASE TALC MIXTURE % REDUCTION 10010 11 150 16 16 200 21 21 300 31 28 400 44 37 500 66 50 600 80 65 19%

The lubricity results of Example 1, Test 3 indicate an improvement inlubrication was about 19% at the 600 reading on the lubricity tester.

EXAMPLE 1

Test 4: Texture of Dynamic Filter Cake Surfaces

The texture of the filter cake surfaces and the surfaces of the base mudwere also tested. The results were as follows: the texture of thesurface of the base mud was extremely smooth and shinny. The texture ofthe Dynamic Filter Cake Surface of the base mud treated with 2% byvolume of the talc, bead and oil mixture was shinny and the copolymerbeads could be seen impregnated in the cake as well as protruding on thesurface of the cake.

EXAMPLE 2

Test 1: Rheology & HPHT Results

In Example 2, a 16.9 pound per gallon water-based drilling fluid wastested for the (a) the compatibility of the drilling fluid-such asrheology; and the yield point and gels in particular; (b) the highpressure high temp fluid loss-HPHT; (c) the filter cake wt./gram; and(d) the filter cake thickness (in inches). Parameters were first testedon the base mud. By comparison, 2 percent (%) by volume of the oil, talcand the beads mixture was added to the base drilling fluid and mixed for5 minutes on a Waring blender. In Example 2, Test 1, the followingrheology and HPHT results were noted in Table 5 below:

TABLE 5 Rheology & HPHT Results BASE & 2% % BASE TALC MIXTURE REDUCTIONDensity 16.9 PH Meter 10.4 600 rpm 53 56 300 rpm 30 32 200 rpm 22 25 100rpm 13 15 6 rpm 2 3 3 rpm 1 2 PV @ 120 F. 23 24 YP 7 8 Gels 10 sec/10min {fraction (4/19)} {fraction (5/27)} HPHT @ 300 Deg F./ml 15.0 13.212% Cake Wt./g 27.2 18.7 31% Cake Thickness/inch {fraction (6/32)}{fraction (4/32)} 33%

The results of Example 2, Test 1 indicate the following: in Test 2,Table 5, the talc, beads and oil mixture was very compatible with themud rheology with little change points and gel. The HPHT fluid loss wasreduced from 15.0 to 13.2, a 12% reduction, which is somewhat less thanexpected. The cake weight in grams was reduced from 27.2 grams to 18.7grams, a 31% reduction, which is a very good result. The cake thicknesswas reduced from 6/32 to 4/32, a 33% reduction.

EXAMPLE 2

Test 2: Dynamic Filtration

In Example 2, Test 2, the following dynamic filtration criteria weretested: (a) Fluid loss versus time; (b) Filter cake wt/gram; and (c)Filter cake thickness in inches. The dynamic filtration data of Example2, Test 2 is set forth in Table 6 below:

TABLE 6 DYNAMIC FILTRATION 10 Darcy, 35 Micron Filter Media 300 DegreesF., 600 rpm @ 1000 PSI for 60 Minutes Fluid Loss ml BASE & 2% TIMEMinutes BASE TALC MIXTURE % REDUCTION Initial Spurt 1.0 0.5 15 25.2 17.630 38.0 25.0 45 46.0 31.4 60 53.2 36.0 32% Cake Wt/g 91 62 32% CakeThickness/Inch {fraction (18/32)} {fraction (12/32)} 33%

The results of Example 2, Test 2, Table 6 are as follows: after 60minutes, the dynamic fluid loss was reduced from 24.0 ml to 16.8 ml, a32% reduction, which is an excellent result. The cake weight in gramswas reduced from 91 grams to 62 grams, a 32% reduction, which is a verygood result. The filter cake was reduced from 18/32 to 12/32, a 33%reduction, which is also an excellent result.

EXAMPLE 2

Test 3: Lubricity Test

Table 7 below shows the test results of the lubricity of the additive astorque is applied.

TABLE 7 LUBRICITY TEST @ 60 rpms Co-efficient of Friction of Water(0.33-0.36) = 0.33; i.e. reading at 150 inch pounds is 33 LubricityReading (electric current required to sustain 60 rpm at applied torque)Applied Torque/Inch BASE & 2% Pounds BASE TALC MIXTURE % REDUCTION 10014 9 150 23 12 200 30 15 300 46 20 400 60 23 500 76 25 600 92 28 70%

The lubricity results of Example 2, Test 3 indicate an improvement inlubrication was about 70% at the 600 reading on the lubricity tester,which is an excellent result.

EXAMPLE 2

Test 4: Texture of Dynamic Filter Cake Surfaces

The texture of the filter cake surfaces and the surfaces of the base mudwere also tested. The results were as follows: the texture of thesurface of the base 16.9 ppg mud was smooth and shinny. The texture ofthe Dynamic Filter Cake surface of the base mud treated with 2% byvolume of the talc, bead and oil mixture was shinny and the copolymerbeads could be seen impregnated in the cake as well as protruding on thesurface of the cake.

EXAMPLE 3

Reduction in Capillary Attractive Forces of Examples 1& 2

In Example 3, the (dynamic) filter cake of the base mud was placed on aflat surface and a piece of glass_inch thick and four inches square wasplaced flat on the surface of the base mud filter cake and allowed tosit for thirty minutes. An attempt was then made to lift the glass fromthe filter cake. As the glass plate was lifted, the filter cake followedand it was as though the filter cake was glued to the glass.

The (dynamic) filter cake of the base mud to which 2% of the additive ofthe present invention was added was placed on the flat surface and thesame process discussed above was duplicated. It was found that the pieceof glass easily separated from the filter cake surface, which wastreated with the additive of the present invention. The results showthat the additive mixture of the present invention definitely reduced,if not, eliminated the capillary attractive forces of the wall cake.

Since the above tests were conducted in open air on the counter top, itwas determined that the same tests should be conducted while totallysubmerged in the drilling fluid. In running the same tests with thefilter cake and the 4 inch piece of glass completely submerged in thedrilling fluid, it would be concluded that no air would be present inthe filter cake or the glass surface and such a test would resemble awellbore filled with drilling fluid. This test results were as follows:the glass plate stuck more firmly to the submerged water-based mud wallcakes than it did in open air; and the glass plate would not stick tothe wall cakes of the water-based muds, which were treated with the 2%by volume of the drilling fluid additive of the present invention.

Numerous modifications and variations of the present invention arepossible in light of the above teachings. It is therefore to beunderstood that within the scope of the attendant claims attachedhereto, this invention may be practiced otherwise than as specificallydisclosed herein.

What is claimed is:
 1. A drilling fluid additive manufactured by amethod comprising of: admixing talc with oil and glycol to create asuspended mixture, said suspended mixture allowing the surface of saidtalc to be pre-wet with said oil and said glycol; admixing copolymerbeads to said suspended mixture to thereby allow said beads to bepre-wet with said oil and said glycol prior to adding said mixture to adrilling fluid.
 2. The drilling fluid additive of claim 1 wherein saidbeads have a specific gravity at from about 1.0 to about 1.5 and a sizefrom about 40 microns to about 1500 microns.
 3. The drilling fluidadditive of claim 1 wherein said beads are comprised of styrene anddivinylbenzene.
 4. The drilling fluid additive of claim 1 wherein saidtalc has a size range from about 2 microns to about 40 microns.
 5. Thedrilling fluid additive of claim 1 wherein said oil consist essentiallyof oils, hydrocarbon oils, vegetable oils, mineral oils, paraffin oils,synthetic oils, diesel oils animal oils, soybean oil and mixturesthereof.
 6. The drilling fluid additive of claim 1 wherein said glycolconsist essentially of polypropylene glycol, polyethoxylated glycol,polybutylene glycol, polyethylene glycol, propylene glycol, polyesterpolyol-poly(oxyethylene-oxy) propylene glycol, polyoxyalkylene glycolethers and mixtures thereof.
 7. The drilling fluid additive of claim 1wherein said talc comprises from about 2% to about 50% of said additive.8. The drilling fluid additive of claim 1 wherein said oil comprisesfrom about 50% to about 86% of said additive.
 9. The drilling fluidadditive of claim 1 wherein said glycol comprises from about 10% toabout 46% of said additive.
 10. The drilling fluid additive of claim 1wherein said beads comprises from about 2% to about 50% of saidadditive.
 11. A drilling fluid additive manufactured by a methodcomprising of: admixing talc with cellulose to create a suspendedmixture, said suspended mixture allowing the surface of said talc to becoated with said cellulose; admixing copolymer beads to said suspendedmixture to thereby allow said beads to be pre-wet with said celluloseprior to adding said mixture to a drilling fluid.
 12. The drilling fluidadditive of claim 11 wherein said beads have a specific gravity at fromabout 1.0 to about 1.5 and a size from about 40 microns to about 1500microns.
 13. The drilling fluid additive of claim 11 wherein said beadsare comprised of styrene and divinylbenzene.
 14. The drilling fluidadditive of claim 11 wherein said talc has a size range from about 2microns to about 40 microns.
 15. The drilling fluid additive of claim 11wherein said cellulose consist essentially of polyanionic cellulose,polyanionic cellulose polymer, and carboxymethylcellulose.
 16. Thedrilling fluid additive of claim 11 wherein said talc comprises fromabout 2% to about 50% of said additive.
 17. The drilling fluid additiveof claim 11 wherein said cellulose comprises from about 5% to about 96%of said additive.
 18. The drilling fluid additive of claim 11 whereinsaid beads comprises from about 2% to about 50% of said additive.
 19. Amethod of manufacturing a drilling fluid additive, said methodcomprising: shearing talc with oil and a glycol to create a suspendedmixture to thereby allow the surface of said talc to be pre-wet withsaid oil and said glycol; and admixing copolymer beads to said suspendedmixture.
 20. The method of claim 19 wherein said beads have a specificgravity at from about 1.0 to about 1.5 and a size from about 40 micronsto about 1500 microns.
 21. The method of claim 19 wherein said beads arecomprised of styrene and divinylbenzene and further comprising: addingsaid suspended mixture to a water-based drilling fluid; and pumping thefluid with said additive into a well bore.
 22. The method of claim 19wherein said talc have a size range from about 2 microns to about 40microns.
 23. The method of claim 19 wherein said oil consist essentiallyof oils, hydrocarbon oils, vegetable oils, mineral oils, paraffin oils,synthetic oils, diesel oils, animal oils, soybean oil and mixturesthereof.
 24. The method of claim 19 wherein said glycol consistessentially of polypropylene glycol, polyethoxylated glycol,polybutylene glycol, polyethylene glycol, propylene glycol, polyesterpolyol-poly(oxyethylene-oxy) propylene glycol, polyoxyalkylene glycolethers and mixtures thereof.
 25. The method of claim 19 wherein saidtalc comprises from about 2% to about 38% of said additive, said oilcomprises from about 50% to about 86% of said additive, said glycolcomprises from about 10% to about 46% of said additive and said beadscomprises from about 2% to about 38% of said additive.
 26. A method ofmanufacturing a water-based drilling fluid, said method comprising:shearing talc with cellulose to create a suspended mixture to therebyallow said talc to be coated with said cellulose; admixing copolymerbeads to said suspended mixture thereby allowing said beads to be coatedwith said cellulose and shearing until a homogeneous mixture is formed;adding said suspended mixture to a water-based drilling fluid; andpumping the fluid with said additive into a well bore.
 27. The method ofclaim 26 wherein said beads have a specific gravity at from about 1.0 toabout 1.5 and a size from about 40 microns to about 1500 microns, saidbeads are comprised of styrene and divinylbenzene.
 28. The method ofclaim 26 wherein said talc comprises from about 2% to about 50% of saidadditive, said cellulose comprises from about 5% to about 96% of saidadditive and said beads comprises from about 2% to about 50% of saidadditive.
 29. A drilling fluid additive system comprising: talc, oil,glycol and copolymer beads.
 30. A drilling fluid additive systemcomprising: talc, cellulose and copolymer beads.